The invention relates to an extrusion machine having a machine frame, an extrusion press, a material inlet opening and a material outlet opening, from which a material flow passes in one direction, a drive for the extrusion press and a die located in the vicinity of the material outlet opening, together with a cutting tool associated with said die, a changer mechanism being provided, which has a support member for at least two interchangeable dies and/or cutting tools, and the support member is movably positioned with respect to the extrusion press in the vicinity of the material outlet opening.
When operating the extrusion press it is necessary at certain time intervals to replace the die and/or cutting tool. In the case of extrusion machines with a die and cutting tool fitted in stationary manner it is firstly necessary to stop the extrusion press, so that the production process is interrupted. Following the replacement of the die or cutting tool production must be restarted. However, said starting process yields a certain production waste until the production process has been set up again in such a way that the desired quality is obtained.
For extruding detergents there are e.g. production processes in which initially dry substances are weighed out and then transported over several floors to a mixer, where different liquids are added to the pulverulent substances. The mixture is then supplied to the extruder. If, as a result of a change of a die or a cutting tool on the extruder, said production process has to be interrupted, a charge of dry product remains in the mixer. On restarting the production installation this dry product must firstly be discharged upstream of the extruder, because otherwise it would lead to a blocking of the extruder screw. Therefore firstly the mixing process must be started up to such an extent that the mixer supplies a desired, extrudable preliminary product. Until the mixture delivered by the mixer is sufficiently plastic, several hundred kg of material is discharged upstream of the extruder. Hitherto the checking of the mixture delivered by the mixer has taken place in a manual manner and is both time and labour-consuming. If this work prior to the restarting of the extrusion machine is not performed in a conscientious manner, it is necessary to clean the extruder in all the production-carrying members.
A replacement of a die or a cutting tool in such an extrusion machine consequently not only leads to a loss of production during the changing work, but also to a significant production loss on restarting the extrusion machine.
In a known extrusion machine this production loss is avoided in that the die and the cutting tool are automatically changed by a changer mechanism at the material outlet opening of the extrusion press. The change takes place in such a way that an interruption to the operation of the extrusion press is no longer necessary.
In the known extrusion machine the changer mechanism with the drive and the interchangeable tools are located at the material outlet opening of the extrusion press. This arrangement is particularly advantageous if sufficient space is available in the vicinity of the material outlet opening.